I had
already detailed how I wanted to improve the stability of the machine. I did add
two more idler casters which alone increased the stability of the turntable
greatly. The extra idler casters are small things. The diameter of the the
wheels are about 35mm (1.5") and about 12mm (0.5") wide. Pretty small, but I
didn't want bigger ones as they take up more space underneath the turntable. The
width of the wheels are a bit too wide for my liking (friction!) and I'll
replace then with narrower (approx. 6-7mm thickness) later. Improvements to
improvements as it were. You can see the drivewheel and one of the idler casters
in this picture.
The next and more complicated
improvement was the construction of a small gear box to attach to the drive pin
of the motor driving the turntable. You can see a pictures here and here of two different incarnations of the gear
box. Perhaps 'complicated' is a slight exaggeration. It felt like it was
complicated because it too me a while to get it working the way I wanted it to.
I had some cog wheels lying around from a previous project that never got
started. I had purchased these cogs from a model toy shop. I mounted two of
these cogs in a small metal frame. I made the metal frame from two pieces of
punched plate bent into an 'L' form and drilled to support the shafts - 6mm
threaded rods! - holding the cogs. You can see in the previous picture how I
also reinforced the 'L' shaped plates to add further stability. Here's a close up
of what it the gear box looks like. A 40 toothed wheel was mated to a 15 toothed wheel. The drive pin of the 12V
wiper motor connects to the 40 tooth cog and the drive wheel connects to the 15 tooth
cog as can be seen in one of the photos above.
Conclusions so far.
This improvement was worth it! The machine is so much more stable and robust. I don't have
any doubt that the machine is now capable of tackling a much larger mirror.
Recent notes.
Well I've been fiddling with the
turntable again. I decided to try and increase the stability of the spindel. The
original spindel as such worked fine. I just had an itch to experiment. I was
thinking that it would be nice if I had a bit more control over the height and
stability of the turntable. I decided to construct a new base for the
turntable. Instead of a single spindel supporting the turntable I now
have four (4). Have a look here. Do you see what I have done?
Remember this? The original base plate with a "U"
shaped piece of metal soldered to it? Well instead of the u-piece I soldered another
inverted base plate (minus the ball bearing assembly) to the original base
plate assembly. The four threaded rods are connected to this second base
plate and allows me a certain amount of adjustment (up/down/tilt) of the turntable.
And it's rock steady. I enclosed the gear assembly in a little box as
well to keep dirt and dust out of the gears. See here. It looks a lot less cluttered.
You can see that I also mounted the motor and gear assembly onto a base board.
It makes it easier to place and move the motor assembly around. I also placed
some rubber under the motor (the small black square of material under the motor) to cushion it
and dampen vibrations.
When I get more time I'll add some
more notes. Meanwhile, experiment!
